It’s likely from how it was brewed from what I’ve experienced so far. Some of us are sensitive some like me are very sensitive. Others like snayaz nothing at all
I’ve had it happen with GSO and MCT, so I don’t think it’s oils at all.
I’ve had bad reactions from 3 different labs so far - don’t need to shame them as I don’t think it’s anything they’ve done wrong. Just different ways to brew the same thing
Could be filtering, different BA and BB content that trigger the issues or none of the above and it could also be cleanliness of the lab and sterile equipment etc
So many things it could be so I just stick to the labs that don’t give the reaction